wierd black spot algae?

This is a discussion on wierd black spot algae? within the Beginner Planted Aquarium forums, part of the Beginner Freshwater Aquarium category; -->
my fish tank has been growing this brown algae on the glass walls and for a while my chinese algae eater kept them in ...

my fish tank has been growing this brown algae on the glass walls and for a while my chinese algae eater kept them in check but then the algae eater died and i couldn't get a new one for a while and the algae covered all my walls. Then they started growing these black spots and the new otos i got for the tank cant seem to eat it. Does anyone know what the balck spots are and if they can harm my fish?